Session 2: Organic matter, the key to climate change mitigation?

Organiser: Heike Knicker, University of Seville, Spain


The availability of soil organic nitrogen (SON) determines soil fertility and biomass production to a great extent. SON and SOC are coupled via biomass production and degradation and the narrow C/N ratio of mature soil organic matter (SOM) shows that SON is a major contributor to the humified SOM, determining not only the size of this pool but also its chemical composition. More and more evidences are published showing that black nitrogen (BN) produced during natural and prescribed fires represents an additional source which affects the nature and amount of SON and the turnover rates of SOC in fire-prone regions. Although there is increasing awareness of the impact of the nitrogen (N) cycle on the carbon (C) cycle, the extent of this interaction and the implications for SOM dynamics are still under debate. Comparably, the direct impact of SON on plant growth has become an area of high interest. Therefore, in the present session, we intend to discuss advances concerning the knowledge about the inter-relationships of the soil cycles of C and N, the interaction between SON and plants as well as current ideas about the nature of SON and the mechanisms of its stabilization. The discussed subjects will include progress in:

  1. Methodologies to reveal the nature of SON
  2. The impact of different N-sources (microbial, plant, fire, fertilizer) on size and nature of SON
  • The role of SON for C-sequestration
  1. Understanding the mechanisms controlling the interaction between C and N cycling in soil
  2. Understanding the role of SON for the N-competition between plants and microorganisms
  3. Modeling the interrelationship between C sequestration and N availability and vis-versa

It is expected that this session will not only add to a better understanding of the N cycle in soils but also contribute to improved evaluation of soils as C-sinks.



Will be decided depending on the number of abstracts